USING COMPLEX NUMBERS IN JAVA

The Java math library lacks adequate support for real mathematical
needs, such as working with Complex numbers. However, there are other math
libraries available that assist with Complex numbers in Java calculations.

For example, visit the Java Grande Forum and JavaNumerics Web sites.
They have a collection of proposed standards to aid the Java numerically
challenged, one of which happens to be a Complex number API implementation
by Visual Numerics.
http://clickthru.online.com/Click?q=02-qia9IljcNYED_11_XDdyr_zpb4ZR 
http://clickthru.online.com/Click?q=17-agitI5X-ebidaGFIzyZ3RTj37RsR 
http://clickthru.online.com/Click?q=2c-DatOIc0wqXEG1G2c-PAnBgWJQcuR 

This implementation, VisualNumerics.math.Complex, is simple and easy to
use. It provides all the basic mathematical operations, trigonometric
functions, and a handful of special complex functions. The style of
implementation is similar to the style for java.lang.Math and java.lang.Integer.

First, create the Complex numbers. The Complex class has 4 constructors:

Complex c1 = new Complex(); // equivalent to 0 + 0i
Complex c2 = new Complex(1.0); // equivalent to 1 + 0i
Complex c3 = new Complex(c2); // copy c2
Complex c4 = new Complex(1.0, 1.0); // equivalent to 1 + 1i

NOTE: While the constructors take arguments of type 'double', you can
pass in integers or Double.NaN.

The manipulation of a Complex number is easy. For example:

Complex c1 = new Complex(5,5); // 5 + 5i
Complex c2 = new Complex(2,-6); // 2 - 6i

Complex c = null;

c = c1.add(c2);
System.out.println(c); // 7.0-1.0i

// a static version
c = Complex.add(c1, c2); // 7.0-1.0i
System.out.println(c);

c = c1.subtract(c2);
System.out.println(c); // 3.0+11i

c = c1.multply(c2);
System.out.println(c); // 40.0-20.0i

c = c1.divide(c2);
System.out.println(c); // 5.0+5.0i

In addition to these instance methods, there are many static methods
available, such as static add, subtract, multiply, and divide methods.
Static methods also include complex functions:

Complex c = new Complex(3, 4); // 3+4i
System.out.println( Complex.abs(c) ); // 5.0
System.out.println( Complex.argument(c) ); // 0.9272952180016122
System.out.println( Complex.conjugate(c) ); // 3.0-4.0i

Besides these necessary complex functions, there are trigonometric and
exponential functions.

These examples cover most of the basic Complex number needs, and the
adherence to the Java style and energies of the creators and
standard-bearers should keep your code well placed for the arrival of future standards.

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